Device and method for positional adjustment of light modulator

ABSTRACT

In a light beam sensor ( 40 ) of a position adjuster, a light beam irradiated from a cross dichroic prism ( 150 ) is directly received by a CCD camera ( 41 ) via a beam splitter ( 451 ), so that the position adjuster can be adjusted without using a conventional projection screen and great size reduction of the position adjuster is possible, and, since only small space is required for installing the position adjuster, workspace can be efficiently utilized.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a position adjuster and aposition adjusting method of an optical modulator for adjusting relativeposition of optical modulators used for producing a projector, theprojector having a color separating optical system for separating alight beam irradiated by a light source into a plurality of colorlights, a plurality of optical modulators for modulating the respectivecolor lights separated by the color separating optical system inaccordance with image information and a color combining optical systemfor combining the light beam modulated by the respective opticalmodulators.

[0003] 2. Description of Related Art

[0004] Conventionally, a projector having a plurality of opticalmodulators (liquid crystal panels) for modulating a plurality of colorlights respectively in accordance with image information, a colorcombining optical system (cross dichroic prism) for combining the colorlights modulated by the respective optical modulators, and a projectionoptical system (projection lens) for enlarging and projecting the lightbeam combined by the color combining optical system to form a projectedimage has been used.

[0005] So-called three-plate projector is known as such projector, inwhich a light beam irradiated by a light source is separated into threecolor lights of red, green and blue by a dichroic mirror, the separatedlight beam is modulated for each color light in accordance with imageinformation and the modulated light beam is combined by the crossdichroic prism to enlarge and project the color image through aprojection lens.

[0006] In order to obtain a vivid projection image by the projector, itis necessary to prevent picture element deviation among the respectiveliquid crystal panels and distance gap from the projection lens, so thatfocus and alignment between the respective liquid crystal panels have tobe adjusted with high accuracy in producing the projector.

[0007] The focus adjustment refers to adjustment for accurately locatingthe respective liquid crystal panels at a back focus position of theprojection lens and the alignment adjustment refers to adjustment forcoinciding the picture elements of the respective liquid crystal panels,which also apply in the following description.

[0008] The focus and alignment adjustment of the liquid crystal panelhas been conventionally conducted by adjusting an optical unit includingthree liquid crystal panels, a cross dichroic prism and a projectionlens, where (1) a light beam is irradiated on an image formation area ofthe respective liquid crystal panels, (2) the projected image passingthrough the cross dichroic prism and the projection lens is displayed ona screen, (3) the reflected light of the image projected on the screenis taken by a beam sensor such as a CCD camera fixed at a predeterminedposition and (4) the relative position of the respective liquid crystalpanels is adjusted by a position adjusting mechanism while checking thefocus, picture element position etc. of the respective liquid crystalpanels detected by the CCD camera. In other words, the position of therespective liquid crystal panels has been adjusted based on the positionof the image projected on the screen.

[0009] Conventionally, in order to project an image on a screen, anarrangement where an optical unit and a screen are disposed along anoptical axis of a projection lens and the projected light from theoptical unit is directly projected on the screen (conventionalexample 1) and another arrangement having a reflector for reflecting alight of a light source passing through a liquid crystal panel and aprism along a first direction into a second direction different from thefirst direction and a screen onto which the light of the light sourcereflected by the reflector along the second direction is projected(Japanese Patent Laid-Open Publication No. 2000-147654; conventionalexample 2) have been proposed.

[0010] However, according to the conventional example 1, since the imageis projected on the screen and the optical unit and the screen arelinearly disposed along the optical axis of the projection lens,large-size screen is necessary, thereby increasing the whole size of thedevice.

[0011] In the conventional example 2, though the size of the screen canbe reduced-as compared to the conventional example 1 by reflecting thelight projected by the projection lens with the reflector through amirror, there is certain limit in size reduction of the whole devicebecause of the use of the screen.

[0012] Accordingly, since the screen is necessary in both arrangements,large-scale device is necessary and solution thereof has been stronglydesired.

SUMMARY OF THE INVENTION

[0013] An object of the present invention is to provide a positionadjusting device and a position adjusting method of an optical modulatorcapable of greatly reducing the size of the whole device.

[0014] In order to achieve the above object, in the present invention,the relative position of the optical modulators is adjusted withoutusing the screen that has been conventionally used.

[0015] Specifically, a position adjuster of an optical modulator of thepresent invention adjusts relative position of a plurality of opticalmodulators, the position adjuster being used for producing a projectorhaving a color separating optical system that separates a light beamirradiated by a light source into a plurality of color lights, aplurality of optical modulators that modulates the respective colorlights separated by the color separating optical system in accordancewith image information, and a color combining optical system thatcombines the light beam modulated by the optical modulators, theposition adjuster including a light beam sensor that directly receives aposition-adjusting light beam irradiated by the optical modulatorthrough the color combining optical system.

[0016] According to the present invention, since the light beamirradiated by the color combining optical system is directly received bythe light beam sensor, no projection screen is required, thus greatlyreducing entire size of the apparatus and achieving the above object.

[0017] In the position adjuster of an optical modulator according to thepresent invention, the light beam sensor may preferably include: a lightguide that introduces the light beam irradiated by the color combiningoptical system in a predetermined direction; and an image sensor thatreceives the light beam guided by the light guide and converts the lightbeam into an electric signal.

[0018] According to the above arrangement, since the image sensor can befreely located by the provision of the light guide, the locationefficiency of the respective components of the position adjuster of theoptical modulator can be improved, thereby further enhancing sizereduction of the position adjuster.

[0019] In the above arrangement, the light guide may preferably includea reflection mirror that reflects and refracts the light beam irradiatedby the color combining optical system.

[0020] According to the above arrangement, since only the reflectionmirror is required on the light beam emitting side of the colorcombining optical system, the arrangement of the light beam sensor canbe simplified.

[0021] Alternatively, the light guide may preferably include an opticalfiber that introduces the light beam irradiated by the color combiningoptical system to the image sensor.

[0022] According to the above arrangement, since the optical fiber isflexible, the freedom of location of the image sensor can be improved,thereby further enhancing size reduction of the position adjuster.

[0023] In the above, the light beam sensor may preferably include alight supply that supplies the position-adjusting light beam.

[0024] According to the above arrangement, since the light beam is notnecessarily supplied from the incident-side of the optical modulator,light beam supply portion is not necessary to be provided on themechanism used in adjusting position of the optical modulator, therebysimplifying the structure of the mechanism.

[0025] In the position adjuster of the present invention, the light beamsensor may preferably include a plurality of image sensors.

[0026] According to the above arrangement, when the focus and alignmentof the optical modulator are adjusted, since the image of a plurality ofpicture element area can be taken, the adjustment can be conducted withhigh accuracy by adjusting the focus and alignment on all of the imagingareas.

[0027] In the above, the plurality of image sensors may preferably becorrespondingly located on a diagonal line of a rectangular imageformation area of the optical modulator.

[0028] Accordingly, when a plurality of components such as CCD cameraincluding the image sensor and signal processor are provided, mutualinterference can be avoided.

[0029] In the position adjuster according to the present invention, aposition adjusting portion that holds the optical modulator and adjuststhe position of the optical modulator relative to the color combiningoptical system may preferably be provided, the position adjustingportion being supported by a coarse focus adjusting mechanism that ismoved toward and away from the color combining optical system.

[0030] According to the above arrangement, since the position adjustingportion is supported by the coarse focus adjusting mechanism, bylocating the position adjusting portion at a predetermined positionrelative to the coarse focus adjusting mechanism, the optical modulatorcan be set at a designed predetermined position relative to the colorcombining optical system by moving the coarse focus adjusting mechanismby a predetermined distance from the condition holding the opticalmodulator by the position adjusting portion.

[0031] A position adjusting method of an optical modulator according toanother aspect of the present invention uses the above-describedposition adjuster. Specifically, the position adjusting method of anoptical modulator of the present invention adjusts relative position ofa plurality of optical modulators, the position adjusting method beingused for producing a projector including a color separating opticalsystem that separates a light beam irradiated by a light source into aplurality of color lights, a plurality of optical modulators thatmodulates the respective color lights separated by the color separatingoptical system in accordance with image information, and a colorcombining optical system that combines the light beam modulated by theoptical modulators, the position adjusting method including: apreliminary step that, based on a plurality of reference opticalmodulators and a reference color combining optical system of whichrelative position is adjusted in advance, sets a position of light beamsensor capable of receiving a light beam irradiated by the referencecolor combining optical system; a provision step that sets the colorcombining optical system relative to the light beam sensor; a detectionstep that introduces the light beam to the optical modulator to beadjusted for directly detecting the light beam irradiated via the colorcombining optical system by the light beam sensor; and a positionadjusting step that adjusts the position of the optical modulator basedon the detected light beam

[0032] According to the above method, the light beam sensor can be setat an appropriate position based on the reference optical modulator andthe reference color combining optical system by the preliminary step,and the position of the optical modulator can be adjusted withoutprojecting the projection image on the screen by the provision step,detection step and position adjusting step. Accordingly, the size of theposition adjuster required for adjustment work can be greatly reducedsince the screen is not necessary, thereby achieving the above object.

[0033] In the position adjusting method of an optical modulatoraccording to the present invention, the detection step and the positionadjusting step may preferably be continuously conducted for everyoptical modulator.

[0034] Accordingly, the light beam sensor can be commonly used by therespective optical modulators, so that the adjustment can be conductedwith a small number of light beam sensor.

[0035] In the position adjusting method of an optical modulatoraccording to the present invention, the preliminary step may preferablyhave an initial setting step where a position of a position adjustingportion that adjusts the position of the optical modulator at a designedpredetermined position relative to the coarse focus adjusting mechanismmoving toward and away from the color combining optical system.

[0036] According to the above method, since the preliminary step has theinitial setting step, by locating the optical modulator on the positionadjusting portion before or after the initial setting step, the positionadjuster can be located at a predetermined position relative to thecoarse focus adjusting mechanism by the initial setting step, so thatthe optical modulator can be located at a designed predeterminedposition relative to the color combining optical system by moving thecoarse focus adjusting mechanism relative to the color combining opticalsystem by a predetermined distance.

[0037] Accordingly, the position adjustment of the optical modulatorduring the position adjusting step can be simplified, thereby reducingthe cycle time.

[0038] Further, in the position adjusting method of an optical modulatoraccording to the present invention, the position adjusting step maypreferably include a focus adjusting process where advancement andretraction positions relative to the color combining optical system areadjusted and an alignment adjusting process where the mutual position ofrespective optical modulators is adjusted.

[0039] According to the above method, since the position adjusting stepincludes the focus adjusting process and the alignment adjustingprocess, the planar position, the in-plane rotary position and theout-plane rotary position of the optical modulator can be adjusted whilethe advancement and retraction position of the optical modulatorrelative to the color combining optical system are adjusted.

[0040] Therefore, the optical modulator can be located at a desiredposition relative to the color combining optical system by locating theoptical modulator at the back focus position of the projection lens andadjusting the mutual position of the respective optical modulators.

[0041] In the position adjusting method of an optical modulatoraccording to the present invention, the focus adjusting process maypreferably include a coarse adjusting step where the focus of theoptical modulator is adjusted by advancing and retracting a coarse focusadjusting mechanism that moves the optical modulator toward and awayfrom the color combining optical system, and a minute adjusting step bythe position adjusting portion that adjusts the position of the opticalmodulator.

[0042] According to the above method, since the focus adjusting stepincludes the coarse adjusting step and the minute adjusting step, themovement range of the optical modulator can be set wide by adjusting themovement of the optical modulator so that the optical modulator is movedin the range of millimeter to centimeter order during the coarseadjusting step and is moved in the range of micrometer to millimeterorder during the minute adjusting step, thereby easily and rapidlyadjusting the position of the optical modulator.

[0043] In the position adjusting method of an optical modulatoraccording to the present invention, the position of the opticalmodulator may preferably be successively adjusted for a plurality ofprojectors, the method comprising a type determining step in whichwhether the same type of projectors are successively produced or not isdetermined, where the initial setting step is omitted when the type ofthe projectors are determined to be the same in the type determiningstep.

[0044] When the position of the optical modulators is successivelyadjusted for a plurality of projectors, the initial setting step can beomitted for the projector produced after the first projector byadjusting the position of the optical modulator relative to the colorcombining optical system based on the initial position set during theinitial setting step established in producing the first projector.

[0045] Similarly, the coarse adjusting step can be omitted for theprojector produced after the first projector by holding the focusposition established in the coarse adjusting step in producing the firstprojector and adjusting the position with the focus position as theinitial position.

[0046] In the present arrangement, when a plurality of projectors areproduced and the position of a plurality of optical modulators issuccessively adjusted relative to the color combining optical system,whether the same model is successively produced or not is determined bythe model determining step and the initial setting step and/or thecoarse adjusting step is omitted when production of the same model isdetermined, so that excessive process in successively producing the samemodel can be omitted.

[0047] Accordingly, the cycle time for producing the projector can bereduced and the position of a plurality of optical modulators can besuccessively and smoothly conducted in accordance with a plurality ofprojectors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0048]FIG. 1 is a schematic illustration showing a structure of aprojector including an optical modulator to be adjusted by a positionadjuster according to respective embodiments of the present invention;

[0049]FIG. 2 is an exterior perspective view showing a structure of aprimary portion of a projector according to the respective embodiments;

[0050]FIG. 3 is an exploded perspective view showing an opticalmodulator to be adjusted of the aforesaid respective embodiments;

[0051]FIG. 4 is a side elevational view showing a position adjustor ofthe aforesaid respective embodiments;

[0052]FIG. 5 is a plan view showing a position adjuster according to theaforesaid respective embodiments;

[0053]FIG. 6 is a side elevational view showing a position adjustingmechanism of the position adjuster according to the aforesaid respectiveembodiments;

[0054] FIGS. 7(A), (B), (C) are front elevational views showing aportion to be irradiated by an adjusting light source according to theaforesaid respective embodiments;

[0055]FIG. 8 is a plan view schematically showing a light beam sensor ofthe position adjuster according to the aforesaid respective embodiments;

[0056]FIG. 9 is a front elevational view schematically showing a lightbeam sensor of the position adjuster according to the aforesaidrespective embodiments seen from IX-IX line of FIG. 8;

[0057]FIG. 10 is a block diagram showing a structure of an inside of acomputer for controlling the position adjuster of the aforesaidrespective embodiments;

[0058]FIG. 11 is an illustration showing a display screen for displayinga fetched image of the aforesaid respective embodiments;

[0059]FIG. 12 is a flowchart for explaining a position adjusting methodof the aforesaid respective embodiments;

[0060]FIG. 13 is an illustration showing a measurement point of focusadjustment used in the aforesaid respective embodiments;

[0061]FIG. 14 is an illustration showing a reference pattern BP forfocus adjustment used in the aforesaid respective embodiments;

[0062]FIG. 15 is a flowchart for illustrating a preliminary step in thefirst embodiment;

[0063]FIG. 16 is a flowchart for illustrating a focus adjustment step inthe aforesaid first embodiment;

[0064] FIGS. 17(A) and (B) are illustrations showing a calculation of apeak position in the focus adjustment step in the aforesaid respectiveembodiments, FIG. 17(B) being an enlarged view of the peak position inFIG. 17(A);

[0065]FIG. 18 is a flowchart for showing a preliminary step in thesecond embodiment;

[0066]FIG. 19 is a flowchart showing a focus adjustment step in thesecond embodiment;

[0067]FIG. 20 is a plan view showing a modification of the presentinvention; and

[0068]FIG. 21 is a plan view showing another modification of the presentinvention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT(S)

[0069] An embodiment of the present invention will be described belowwith reference to attached drawings.

[0070] [1. Structure of Projector to Which Lens Array is Applied]

[0071]FIG. 1 shows a structure of a projector 100 including a pluralityof optical modulators to be adjusted by the position adjuster accordingto an embodiment of the present invention and a color combining opticalsystem.

[0072] The projector 100 includes an integrator illumination opticalsystem 110, a color separating optical system 120, a relay opticalsystem 130, an electric optical device 140, a cross dichroic prism 150as a color combining optical system and a projection lens 160.

[0073] The integrator illuminating optical system 110 has a light source111 including a light source lamp 111A and a reflector 111B, a firstlens array 113, a second lens array 115, a reflection mirror 117 and asuperimposing lens 119. The irradiating direction of the light beamirradiated by the light source lamp 111A is aligned by the reflector111B and the light beam is separated into a plurality of sub-beams bythe first lens array 113. After the irradiating direction of the lightbeam is bent by the reflection mirror 117 for ninety degrees, the lightbeam focuses around the second lens array 115. The respective sub-beamsirradiated by the second lens array 115 are incident on the incidentsurface of the subsequent superimposing lens 119 so that the centralaxis (main beam) thereof becomes perpendicular thereto. Further, theplurality of sub-beams irradiated by the superimposing lens 119 aresuperimposed on three liquid crystal panels 141R, 141G and 141Bconstituting below-described electric optical device 140. The colorseparating optical system 120 has two dichroic mirrors 121 and 122 and areflection mirror 123, the dichroic mirrors 121 and 122 and thereflection mirror 123 separating the plurality of sub-beams irradiatedby the integrator illuminating optical system 110 into three colorlights of red, green and blue.

[0074] The relay optical system 130 includes an incident-side lens 131,a relay lens 133 and reflection mirrors 135 and 137, which introducesthe color light separated by the color separating optical system 120,for instance, blue light B, to the liquid crystal panel 141B.

[0075] The electric optical device 140 has the liquid crystal panels141R, 141G and 141B as three optical modulators, which use, forinstance, polysilicon TFT as a switching element. The respective colorlights separated by the color separating optical system 120 aremodulated by the three liquid crystal panels 141R, 141G and 141B inaccordance with image information to form an optical image.

[0076] The cross dichroic prism 150 as a color combining optical systemcombines images modulated for every color light irradiated by the threeliquid crystal panels 141R, 141G and 141B to form a color image.Incidentally, in the cross dichroic prism 150, dielectric multi-layerfilm for reflecting red light and a dielectric multi-layer film forreflecting blue light are formed in approximate X-shape along a borderof four right-angle prisms, the dielectric multi-layer film combiningthe three color lights. The color image combined by the cross dichroicprism 150 is irradiated by the projection lens 160 and is enlarged andprojected on the screen.

[0077] [2. Structure of Optical Unit]

[0078] In such projector 100, the electric optical device 140, the crossdichroic prism 150 and the projection lens 160 are integrated as anoptical unit 170. Specifically, as shown in FIG. 2, the optical unit 170has a head 171 as a L-shaped side assembly made of magnesium alloy etc.

[0079] The projection lens 160 is fixed by a screw on an outside ofL-shaped perpendicular surface of the head 171. The cross dichroic prism150 is also fixed by a screw on the L-shaped horizontal surface of thehead 171.

[0080] The three liquid crystal panels 141R, 141G and 141B constitutingthe electric optical device 140 surround the three sides of the crossdichroic prism 150. Specifically, as shown in FIG. 3, the respectiveliquid crystal panels 141R, 141G and 141B are accommodated in a holdingframe 143 and are fixed on the cross dichroic prism 150 by a POP (PanelOn Prism) structure where the liquid crystal panels are adhered andfixed on a beam-incident end surface 151 of the cross dichroic prism 150by inserting a transparent resin pin 145 to a hole 143A formed on fourcorners of the holding frame 143 together with an ultraviolet curingadhesive. A rectangular opening 143B is formed on the holding frame 143through which the respective liquid crystal panels 141R, 141G and 141Bare exposed to form an image formation area. In other words, therespective color lights R, G and B are introduced to the exposed part ofthe respective liquid crystal panels 141R, 141G and 141B to form anoptical image in accordance with image information.

[0081] According to the optical unit 170 employing such POP structure,since the focus adjustment, alignment adjustment and fixing process ofthe respective liquid crystal panels 141R, 141G and 141B have to besimultaneously conducted (within approximately eight minutes) inadhering and fixing the liquid crystal panels 141R, 141G and 141B to thecross dichroic prism 150, assembly process is usually conducted asfollows.

[0082] 1) First liquid crystal panel, the liquid crystal panel 141G forinstance, is adhered and fixed on the cross dichroic prism 150.Specifically, the pin 145 coated with ultraviolet curing adhesive at adistal end thereof is inserted to the hole 143A of the holding frame 143of the liquid crystal panel 141G.

[0083] 2) Subsequently, the distal end of the pin 145 is abutted to thebeam-incident end surface 151 of the cross dichroic prism 150.

[0084] 3) The light beam is introduced to the image formation area ofthe liquid crystal panel 141G in the above condition, and while directlychecking the light beam irradiated by the cross dichroic prism 150,advancement and retraction position, planar position and rotary positionrelative to the beam-incident end surface 151 are adjusted to adjustfocus and alignment of the liquid crystal panel 141G.

[0085] 4) When desired focus and alignment are obtained, fixing lightbeam, i.e. ultraviolet, is irradiated from a base end of the pin 145,thereby completely curing the ultraviolet curing adhesive.

[0086] 5) The other liquid crystal panels 141R and 1411B are adhered andfixed in the same manner as the above.

[0087] Accordingly, in order to assemble the optical unit 170 using suchPOP structure, a position adjuster for adjusting relative focus andalignment of the respective liquid crystal panels 141R, 141G and 1411Bis necessary.

[0088] [3. Structure of Position Adjuster of Optical Modulator]

[0089] A position adjuster 2 for adjusting the position of therespective liquid crystal panels 141R, 141G and 141B is shown in FIGS. 4and 5. The position adjuster 2 is composed of a UV light-shield cover20, an adjuster body 30, a light beam sensor 40, a computer 70 (FIG.10), an adjusting light source (not shown) and a fixing ultravioletlight source (not shown).

[0090] The UV light-shield cover 20 has a side plate 21 surrounding anupper part of the adjuster body 30, a bottom plate 22, and a platform 25provided below. Incidentally, an openable and closable door (not shown)is provided on the side plate 21 which is used for supplying andremoving the POP adjustment workpiece and for adjusting the adjusterbody 30 and is formed by an acrylic plate that transmits no ultraviolet.The platform 25 is provided with a castor 25A on the lower side thereofso that the adjuster body 30 can be easily moved in installing thedevice.

[0091] The computer 70 controls the adjuster body 30, the light beamsensor 40, the adjusting light source and the fixing ultraviolet lightsource and is disposed in the platform 25.

[0092] The adjusting light source is a light source of aposition-adjusting light beam used in adjustment work in the adjusterbody 30.

[0093] The fixing ultraviolet light source is a light source of lightbeam (ultraviolet) used for curing ultraviolet adhesive in fixing theliquid crystal panels 141R, 141G and 1411B on the cross dichroic prism150.

[0094] (3-1) Structure of Adjuster Body

[0095] The adjuster body 30 is composed of a six-axis position adjustingunit 31 as a position adjusting portion, a support jig 33 for supportingand holding the cross dichroic prism 150 and a light source unit 37(FIG. 6) for introducing the light beam from the adjusting light sourceand the fixing ultraviolet light source into the liquid crystal panels141 (141R, 141G, 141B).

[0096] The six-axis position adjusting unit 31 adjusts the location ofthe liquid crystal panels 141R, 141G and 141B relative to the lightbeam-incident end surface 151 of the cross dichroic prism 150, which issupported by a six-axis position adjusting unit moving mechanism 31Amovably set along a rail 351 of the bottom plate 22 of the UVlight-shielding cover 20 as shown in FIG. 6.

[0097] The six-axis position adjusting unit moving mechanism 31Asupports the six-axis position adjusting unit 31 and moves the unit inZ-axis direction of the platform 25 (right and left direction in FIG. 6)within a range of millimeter to centimeter order by a drive mechanismsuch as a motor (not shown).

[0098] The six-axis position adjusting unit 31 has a planar positionadjuster 311 supported by the six-axis position adjusting unit movingmechanism 31A, an in-plane rotary position adjuster 313 provided at adistal end of the planar position adjuster 311, an out-plane rotaryposition adjuster 315 provided at a distal end of the in-plane rotaryposition adjuster 313 and a liquid crystal panel holder 317 provided ata distal end of the out-plane rotary position adjuster 315.

[0099] The planar position adjuster 311 adjusts the advancement andretraction position and planar position relative to the lightbeam-incident end surface 151 of the cross dichroic prism 150, whichincludes a base 311A slidably provided on the six-axis positionadjusting unit 31A, a leg 311B vertically mounted on the base 311A, anda connector 311C provided on the upper distal portion of the leg 311Bfor the in-plane rotary position adjuster 313 to be connected. The base311A moves in Z-axis direction (right and left direction in FIG. 6) ofthe platform 25 within a range of micrometer to millimeter order by adrive mechanism such as a motor (not shown). The leg 311B moves inX-axis direction (a direction orthogonal with paper surface of FIG. 6)relative to the base 311A by a drive mechanism such as a motor (notshown) provided on a side thereof. The connector 311C moves in Y-axisdirection (up and down direction in FIG. 6) relative to the leg 311B bya drive mechanism such as a motor (not shown).

[0100] The in-plane rotary position adjuster 313 adjusts the in-planerotary position of the liquid crystal panels 141R, 141G and 141Brelative to the light beam-incident end surface 151 of the crossdichroic prism 150, which includes a cylindrical base 313A fixed to adistal end of the planar position adjuster 311 and a rotation adjuster313B rotatable in the circumferential direction of the base 313A. Byadjusting the rotary position of the rotation adjuster 313B, thein-plane rotary position of the liquid crystal panels 141R, 141G and141B relative to the light beam-incident end surface 151 can be adjustedwith high accuracy.

[0101] The out-plane rotary position adjuster 315 adjusts the out-planerotary position of the liquid crystal panels 141R, 141G and 141Brelative to the light beam-incident end surface 151 of the crossdichroic prism 150. The out-plane rotary position adjuster 315 has abase 315A fixed to a distal end of the in-plane rotary position adjuster313 and provided with a concave curved surface having horizontallyextending arc, a first adjuster 315B slidable along the concave curvedsurface of the base 315A and provided with a concave curved surfacehaving perpendicularly extending arc, and a second adjuster 315Cslidable along the arc on the curved surface of the first adjuster 315B.When the motor (not shown) provided on the side of the base 315A isrotated, the first adjuster 315B is slid. When the motor (not shown)provided on the upper side of the first adjuster 315B is rotated, thesecond adjuster 315C is slid, so that the out-plane rotary position ofthe liquid crystal panels 141R, 141G and 141B relative to the lightbeam-incident end surface 151 can be adjusted with high accuracy.

[0102] The liquid crystal panel holder 317 holds the liquid crystalpanels 141R, 141G and 141B to be adjusted and includes a fixed holdingpiece 317A fixed at a distal portion of the second adjuster 315C, amovable holding piece 317B slidable at a distal portion of the secondadjuster 315C, and an actuator 317C for moving the movable holding piece317B. The liquid crystal panels 141R, 141G and 141B can be held bymoving the movable holding piece 317B by the actuator 317C. Further, bychanging initial slide position of the movable holding piece 317B, theliquid crystal panels 141R, 141G and 141B of different size can be held.

[0103] As shown in FIG. 4, the support jig 33 has a base plate 331provided on the bottom plate 22, a leg 333 vertically mounted on thebase plate 331 and a set plate 335 provided on an upper part of the leg333 for the cross dichroic prism 150 and below-described light guide 45to be attached.

[0104] The light source unit 37 is disposed between the fixed holdingpiece 317A and the movable holding piece 317B of the liquid crystalpanel holder 317 provided to the six-axis position adjusting unit 31.

[0105] The light source unit 37 supplies position-adjusting light beamand fixing light beam to the liquid crystal panels 141R, 141G and 141B,which includes a unit body 371 to be in contact with the liquid crystalpanels 141R, 141G and 141B, and four optical fibers 372 for supplyingthe light from the respective light sources to the unit body 371.

[0106] The base end of the optical fiber 372 is connected to theadjusting light source and fixing light source provided on a lower partof the platform 25. As shown in FIG. 7(A), adjusting light sourceportion 371A located corresponding to corners of the rectangular imageformation area of the liquid crystal panels 141R, 141G and 141B and afixing light source portion 371B located outside the image formationarea to be in contact with the base end of the transparent resin pin 145are provided on the contact surface between the unit body 371 and theliquid crystal panels 141R, 141G and 141B. Incidentally, the unit body371 to be in contact with the liquid crystal panels 141R, 141G and 141Bmay have arrangement different from that shown in FIG. 7(A), where thefixing light source portion 371C is disposed along the outer sideportion of the adjusting light source portion 371A as shown in FIG. 7(B)or the fixing light source portion 371B may be differently arranged asshown in FIG. 7(C). The arrangement of the unit body 371 may be changedin accordance with the type of the liquid crystal panels 141R, 141G and141B, thereby being suitably used for liquid crystal panel of differentfixing structure.

[0107] (3-2) Structure of Light Beam Sensor

[0108] As shown in FIG. 4, the light beam sensor 40 has a CCD camera 41,a moving mechanism 43 adapted to move the CCD camera 41three-dimensionally, and a light guide 45 attached on the support jig33.

[0109] The CCD camera 41 is an area sensor having charge coupled deviceas an image sensor of the present invention, which receivesposition-adjusting light beam irradiated by the cross dichroic prism 150to output as an electric signal.

[0110] As schematically shown in FIGS. 8 and 9, four CCD cameras 41 aredisposed in four directions of the light guide 45 through the movingmechanism 43 (FIG. 4) in the present embodiment. The respective CCDcameras 41 are correspondingly located on diagonal line of therectangular image formation area formed on the liquid crystal panels141R, 141G and 141B. Incidentally, the CCD camera 41 has zooming andfocusing mechanism for detecting the projected image with high accuracy,whereby the zooming and focusing can be more freely adjusted by remotecontrol.

[0111] Though not specifically shown, the moving mechanism 43 includes acolumn vertically mounted on the base plate 331 of the support jig 33, aplurality of shaft members provided on the column, camera attachmentprovided on one of the shaft members, and can move the CCD camera 41 inboth X-axis direction (right and left directions in FIG. 9) and Y-axisdirection (up and down directions in FIG. 9). The movement is effectedby a servo control mechanism inside the platform 25.

[0112] The light guide 45 is composed of four beam splitters 451 asreflection mirror disposed corresponding to four corners of therectangular image formation area of the liquid crystal panels 141R, 141Gand 141B and a holding cover 452 for holding the respective beamsplitters 451 at a predetermined position. The light guide 45 refractsthe light beam on four corners irradiated from the cross dichroic prism150 after being irradiated from the light source unit 37 to the liquidcrystal panels 141R, 141G and 141B by ninety degrees with the respectivebeam splitters 451, and, subsequently, introduces the light beam intothe CCD camera 41. Incidentally, the holding cover 452 is provided withan opening for transmitting the light refracted to the outside. In FIG.8, the light beam is irradiated on the liquid crystal panel 141G.

[0113] According to the light guide 45, the light beam on four cornersirradiated by the cross dichroic prism 150 is directly received by theCCD cameras 41 located in four directions without being projected on thescreen as in the conventional arrangement.

[0114] [4. Adjusting Operation by Position Adjuster]

[0115] The above-described adjuster body 30 and the light beam sensor 40are electrically connected to the computer 70 as shown in block diagramof FIG. 10.

[0116] The computer 70 has a CPU and a storage device, which controlsthe operation of the adjuster body 30 and the light beam sensor 40 andprocesses the projected image taken by the CCD camera 41 of the lightbeam sensor 40.

[0117] The program called by the computer 70 displays a display screen71 shown in FIG. 11 on the display, and the focus and alignment areadjusted based on various information displayed on the display screen71. The display screen 71 includes an image display view 72 for directlydisplaying the image from the CCD camera 41, an image processing view 73for conducting pattern-matching processing of the image displayed on theimage display view 72 based on reference pattern image, and an axismovement display view 74 for displaying adjustment amount of therespective axes of the six-axis position adjusting unit 31 after imageprocessing. Incidentally, the images obtained by the light beam on fourcorners respectively received by the four CCD cameras 41 are displayedon respective image display areas 72A to 72D of the image display view72.

[0118] Next, position adjusting method of the liquid crystal panels141R, 141G and 141B by the position adjuster 2 will be described belowwith reference to flowchart shown in FIG. 12.

[0119] S1: Initially, a master unit having POP structure with the focusposition and alignment position thereof being adjusted in advance inaccordance with the characteristics of the projection lens 160 for eachmodel and the light guide 45 with the location of the beam splitter 451being determined in accordance with the size of the image formation areaof the master unit are set to the support jig 33. The master unit is areference cross dichroic prism as a reference color combining opticalsystem integrated with three reference liquid crystal panels forrespective color lights as reference optical modulators.

[0120] S2: Next, position-adjusting light beam is irradiated on thereference liquid crystal panel of the master unit for green color lightfrom the light source unit 37 and the light beam irradiated by themaster unit is directly received by the CCD camera 41 through the beamsplitter 451. At this time, the moving mechanism 43 is driven to movethe CCD camera 41 to a position capable of securely receiving the lightbeam. The image at this time is displayed on the respective imagedisplay areas 72A to 72D of the image display view 72.

[0121] In the image, for instance, the position moving from the edgecorresponding to the four corners of the reference liquid crystal paneltoward the diagonal inside direction where the picture element areas CAcan be solely displayed on the respective image display areas 72A to 72Das shown in FIG. 13 represents the reference position of the CCD camera41 for focus adjustment. The central area of the picture element area CArepresents the measurement point for conducting focus adjustment.

[0122] Further, as shown in FIG. 14, corresponding edge positions aredisplayed on four corners of some reference liquid crystal panel. In theimage, the substantially square area where the picture element area CAand the area other than the picture element area CA are set at apredetermined ratio is a reference pattern BP for adjusting alignment ofthe liquid crystal panels 141R, 141G and 141B. The position of the CCDcamera 41 at this time is the reference position for each model. Thereference pattern BP is respectively generated for three referenceliquid crystal panels. The reference position for alignment adjustmentof the CCD camera 41 is set only for a single reference liquid crystalpanel.

[0123] The reference pattern BP and the reference position of the CCDcamera 41 are registered to the storage of the computer 70 as a modeldata according to each model.

[0124] The S1 and S2 steps are conducted to a plurality of models inadvance, and the reference pattern BP and reference position of the CCDcamera 41 for each model are registered as model data.

[0125] A designed reference position of the liquid crystal panels 141R,141G and 141B relative to the cross dichroic prism 150 in accordancewith a plurality of models is registered in the model data ascoordinates value.

[0126] S3: Subsequently, the cross dichroic prism 150 is set on thesupport jig 33 (provision step), and the liquid crystal panels 141R,141G and 141B are attached to the liquid crystal panel holder 317 of thesix-axis position adjusting unit 31 while the pin 145 coated with theultraviolet curing adhesive is inserted.

[0127] S4: Next, initializing process is conducted by a program executedby the CPU of the computer 70 prior to actual adjustment work(preliminary step).

[0128] Specifically, the preliminary step is conducted as follows inaccordance with the flowchart shown in FIG. 15.

[0129] S41: The memory such as RAM (Random Access Memory) connected tothe CPU is initialized and the model data registered in advance isfetched in accordance with the type of the cross dichroic prism 150 andthe liquid crystal panels 141R, 141G and 141B.

[0130] S42: The designed coordinates value of the liquid crystal panels141R, 141G and 141B of the model data is read and the initial positionof the planar position adjuster 311, the in-plane rotary positionadjuster 313 and the out-plane position adjuster 315 of the six-axisposition adjusting unit 31 is set relative to the six-axis positionadjusting unit moving mechanism 31A (initial setting step).

[0131] S43: The reference position of the CCD camera 41 of thecorresponding model data is read and the CCD camera 41 is moved to beset at the reference position for focus adjustment.

[0132] S44: The six-axis position adjusting unit moving mechanism 31A isadvanced for a predetermined distance (initial position), so that thepin 145 and the light-incident end surface 151 of the cross dichroicprism 150 are brought into contact.

[0133] At this time, the initial position of the six-axis positionadjusting unit 31 relative to the six-axis position adjusting unitmoving mechanism 31A is set by the initial setting step and the six-axisposition adjusting unit moving mechanism 31A is advanced for apredetermined distance relative to the cross dichroic prism 150, so thatthe liquid crystal panels 141R, 141G and 141B are set at a designedreference position relative to the cross dichroic prism 150.

[0134] S5: Thereafter, the position-adjusting light beam is irradiatedon, for instance, the liquid crystal panel 141G and the light beamirradiated by the cross dichroic prism 150 is directly received by theCCD camera 41 through the beam splitter 451 (detection step).

[0135] S6: The signal from the CCD camera 41 is inputted to the computer70 for conducting focus and alignment adjustment of the liquid crystalpanel 141G by the image processing function thereof (position adjustingstep).

[0136] S61: Initially, the focus of the liquid crystal panel 141G isadjusted in accordance with the flowchart shown in FIG. 16 as follows(focus adjustment step).

[0137] The focus adjustment step S61 is conducted in two stages, i.e. acoarse adjustment step S610 including S611 to S614 and a minuteadjustment step S615 including S616 to S619.

[0138] S611: The planar position adjuster 311 of the six-axis positionadjusting unit moving mechanism 31A is moved by a predetermined distancefrom the initial position for a fixed value designated for each model inthe direction away from the cross dichroic prism 150.

[0139] S612: The luminance at the measurement point on the centralportion of the picture element area CA shown in FIG. 14 of the imageimported by the CCD camera 41 is obtained. The luminance is stored inthe memory of the computer 70 in accordance with the coordinatesposition of the planar position adjuster 311.

[0140] S613: The movement of the planar position adjuster 311 by apredetermined distance in the S611 and the obtainment of the luminanceat the measurement point in the S612 are repeated to obtain theluminance at several points.

[0141] S614: After completion of the above S613, the computer 70calculates the peak position by the luminance obtained in the abovesteps as shown in FIG. 17(A).

[0142] After the coarse adjustment step S610 is completed as in theabove, the planar position adjuster 311 is moved to the peak positioncalculated in S614, where the minute adjustment step S615 is conductedas in the following process.

[0143] S616: The planar position adjuster 311 of the six-axis positionadjusting unit 31 is moved by a predetermined distance from the initialposition to the peak position calculated in S614.

[0144] S617: The image is detected by the CCD camera 41 and theluminance on the measurement point on the central part of the pictureelement area CA shown in FIG. 14 is obtained by the imported image. Theluminance is stored in the memory of the computer 70 in accordance withthe coordinates position of the planar position adjuster 311.

[0145] S618: In S616, the planar position adjuster 311 is moved by asmaller pitch than the movement of the coarse adjustment step S610 andthe obtainment of luminance is repeated at the measurement point toobtain the luminance at several points.

[0146] S619: After completion of S618, the computer 70 calculates thepeak position based on the luminance obtained in the above steps asshown in FIG. 17(B).

[0147] The focus adjustment of the liquid crystal panel 141G iscompleted by moving the planar position adjuster 311 to the peakposition calculated in S619 after completion of the minute adjustmentstep S615.

[0148] S62: After completion of the focus adjustment step S61, thecomputer 70 locates the CCD camera 41 to a reference position foradjusting alignment. Specifically, the steps of S41 and S43 in thepreliminary step S4 are conducted.

[0149] S63: Next, the alignment of the liquid crystal panel 141G isadjusted (alignment adjustment step).

[0150] Initially, STAGE1 representing the six-axis position adjustingunit 31 holding the liquid crystal panel 141G is selected on the displayscreen 71 of a program and the image on the four corners of the liquidcrystal panel 141G is imported by the CCD camera 41. The image importedby the CCD camera 41 is displayed on the image display view 72 of thedisplay screen 71 of the computer 70, where the measurement data ofSTAGE 1 after conducting image-processing is displayed on the imageprocessing view 73.

[0151] In this condition, when Measurement button on the imageprocessing view 73 is pressed, the portion corresponding to thereference pattern BP is detected on the image processing view 73 and theposition of the detected pattern on the screen is detected. Thedeviation of the detected result from the location of the referencepattern BP registered in the S2 step is calculated, the result of thecalculation being displayed on the axis movement display view 74 as themoving amount of the respective axes of the six-axis position adjustingunit 31.

[0152] The computer 70 controls the six-axis position adjusting unit 31based on the moving amount of the respective axes displayed on the axismovement display view 74, thereby adjusting the planar position,in-plane rotary position and out-plane rotary position of the liquidcrystal panel 141G.

[0153] After completing the adjustment step, the Measurement button ispressed again to calculate the moving amount of the respective axes(S64), the process being conducted until the moving amount of all theaxes becomes approximately zero, thereby adjusting the alignment of theliquid crystal panel 141G.

[0154] The coordinates value of the liquid crystal panel 141G relativeto the cross dichroic prism 150 is stored in the memory of the computer70 as a reference data.

[0155] S7: After terminating the focus and alignment adjustment,ultraviolet is irradiated on the pin 145 to fix the liquid crystal panel141G.

[0156] S8: After completing adjustment of the liquid crystal panel 141G,the above steps of S5, S6 and S7 are sequentially conducted on otherliquid crystal panels 141R and 141B.

[0157] Specifically, the steps S5 and S6 are continuously conducted foreach liquid crystal panels 141R and 141B. At this time, the referencedata of the liquid crystal panel 141G is retrieved from the storage tobe used as the initial position of the other liquid crystal panels 141Rand 141B.

[0158] Accordingly, the alignment of the liquid crystal panels 141R and141B can be adjusted while the relative position of the liquid crystalpanels 141R, 141G and 141B are substantially accorded, so that thealignment of the respective liquid crystal panels 141R, 141G and 141Bcan be accurately and smoothly adjusted. At this time, the referencepattern BP corresponding to the liquid crystal panels 141R and 141B isretrieved from the storage to be used.

[0159] S9: In fixing the respective liquid crystal panels 141R, 141G and141B, in order to check the position shift of the respective liquidcrystal panels 141R, 141G and 141B caused on account of curingcontraction of adhesive, position-adjusting light beam is irradiated onthe liquid crystal panels 141R, 141G and 141B to detect the light beamirradiated from the cross dichroic prism 150 directly by the CCD camera41 through the beam splitter 451. The shift of picture element ismeasured by the displayed image.

[0160] S10: The computer 70 controls the actuator 317C and releases therespective liquid crystal panels 141 from being held by the liquidcrystal panels holder 317 of the respective six-axis position adjustingunit 31 and retracts the six-axis position adjusting unit movingmechanism 31A by a predetermined distance to escape the respectivesix-axis position adjusting unit 31 in a direction away from therespective liquid crystal panels 141R, 141G and 141B. Thereafter, theproduced optical unit 170 is removed.

[0161] [5. Advantage of Embodiment]

[0162] According to the present embodiment, following advantages can beobtained.

[0163] (1) In the light beam sensor 40 of the position adjuster 2, sincethe light beam irradiated by the cross dichroic prism 150 is directlyimported by the CCD camera 41 through the beam splitter 451, therespective steps (S1-S7) can be implemented without using theconventional projection screen, so that the size of the positionadjuster 2 can be greatly reduced.

[0164] Accordingly, the space required for installing the positionadjuster can be reduced, thereby enhancing efficiency for using theworkspace.

[0165] (2) Since the light guide 45 having the beam splitter 451 isused, the light beam irradiated by the cross dichroic prism 150 can berefracted by ninety degrees and the CCD cameras 41 can be located aroundthe cross dichroic prism 150. Accordingly, since the CCD camera 41 isnot necessary to be provided along the irradiation direction of thecross dichroic prism 150, the size enlargement of the position adjuster2 in the direction can be prevented, thus further enhancing sizereduction of the position adjuster 2.

[0166] (3) Since the light guide 45 includes the beam splitter 451, thelight guide 45 can be simply constructed with sufficient function andproduction thereof can be conducted with low cost, so that economicalburden can be reduced even when the light guide 45 is prepared for eachmodel.

[0167] Further, though the CCD camera has to be moved with a large-scalemoving mechanism since the projection image size on the screen isgreatly different in the conventional device, in the device of thepresent embodiment, the CCD camera have only to be moved for the sizedifference of the liquid crystal panels 141R, 141G and 141B according torespective models. Accordingly, the size of the moving mechanism 43 canbe reduced and no large-scale moving mechanism is necessary, therebyalso reducing the economic burden therefor.

[0168] (4) Since the light beam sensor 40 is constructed of the four CCDcameras 41, the four corners of the liquid crystal panels 141R, 141G and141B can be taken by the respective CCD cameras 41 and displayed on therespective image display areas 72A to 72D. Accordingly, more accurateadjustment is possible by adjusting focus and alignment at all theimage-taken parts while checking the display condition at the respectiveimage display areas 72A to 72D.

[0169] (5) Since the four CCD cameras 41 are disposed corresponding tothe diagonal line of the rectangular image formation area of the liquidcrystal panels 141R, 141G and 141B, the interference among the CCDcameras 41 can be avoided and the moving mechanism 43 can be easilydisposed using the space between the CCD cameras 41.

[0170] (6) Since the steps S5 and S6 are repeated for each liquidcrystal panel 141R, 141G and 141B, the CCD camera 41 can be commonlyused in adjusting the respective liquid crystal panels 141R, 141G and141B, so that the liquid crystal panels 141R, 141G and 141B can beadjusted by the small number of (four) CCD cameras 41.

[0171] (7) Since the six-axis position adjusting unit 31 is supported bythe six-axis position adjusting unit moving mechanism 31A, the liquidcrystal panels 141R, 141G and 141B can be set at a designedpredetermined position relative to the cross dichroic prism 150 byadvancing the six-axis position adjusting unit moving mechanism 31A by apredetermined distance (S44) while locating the six-axis positionadjusting unit 31 at the initial position relative to the six-axisposition adjusting unit moving mechanism 31A and holding the liquidcrystal panels 141R, 141G and 141B by the liquid crystal panels holder317 of the six-axis position adjusting unit 31 during the initialsetting step S42.

[0172] Accordingly, the position adjustment of the liquid crystal panel141R, 141G and 141B during position adjusting step S6 can be simplifiedand the cycle time can be reduced.

[0173] (8) Since the position adjusting step S6 includes the focusadjustment step S61 and the alignment adjustment step S62, while theadvancement and retraction positions of the liquid crystal panels 141R,141G and 141B relative to the cross dichroic prism 150 are adjusted bythe six-axis position adjusting unit moving mechanism 31A and the base311A of the six-axis position adjusting unit 31, the planar position,the in-plane rotary position and the out-plane rotary position of theliquid crystal panels 141R, 141G and 141B can be adjusted by thesix-axis position adjusting unit 31.

[0174] Accordingly, the liquid crystal panels 141R, 141G and 141B arelocated at a back focus position of the projection lens 160 and themutual position of the respective liquid crystal panels 141R, 141G and141B is adjusted, so that the liquid crystal panels 141R, 141G and 141Bcan be located at an appropriate position relative to the cross dichroicprism 150.

[0175] (9) Since the six-axis position adjusting unit moving mechanism31A moves in a direction toward and away from the cross dichroic prism150 relative to the platform 25 within a range of millimeter tocentimeter order and the base 311A can be moved relative to the six-axisposition adjusting unit moving mechanism 31A in the same direction asthe six-axis position adjusting unit moving mechanism 31A within a rangeof micrometer to millimeter order, the moving range of the liquidcrystal panels 141R, 141G and 141B can be set wide, thereby easily andrapidly conducting the position adjustment of the liquid crystal panels141R, 141G and 141B.

[0176] (10) Since the six-axis position adjusting unit moving mechanism31A can be greatly displaced, the interference of the components can beavoided in attaching the liquid crystal panels 141R, 141G and 141B tothe cross dichroic prism 150 and in removing the integrated liquidcrystal panels 141R, 141G and 141B and the cross dichroic prism 150,thereby enhancing the speed of the process.

[0177] [Second Embodiment]

[0178] Next, the second embodiment of the present invention will bedescribed below.

[0179] In the following, the same reference numeral will be attached tothe structure and components identical with the first embodiment to omitor simplify the detailed description.

[0180] In the position adjuster of the optical modulator in the firstembodiment, the same position adjusting operation is repeated inproducing a plurality of projectors 100 (optical unit 170) using thesame software.

[0181] On the other hand, in the position adjuster of the opticalmodulator according to the present embodiment, when a plurality ofprojectors 100 (optical units 170) are produced, another software isused after the position adjustment is normally completed.

[0182] Specifically, the position adjustment operation of the respectiveliquid crystal panels 141R, 141G and 141B of the initially producedoptical units 170 is conducted in the same manner as the firstembodiment.

[0183] In the optical unit 170 produced after producing the first unit,the position adjustment of the respective liquid crystal panels 141R,141G and 141B is conducted based on the flowcharts shown in FIGS. 12, 18and 19 as follows.

[0184] As in the first embodiment, the model registering operation forregistering the model data corresponding to specific type is conductedin S1 and S2. Thereafter, the cross dichroic prism 150 is set on thesupport jig 33 in the setting step S3 and the liquid crystal panels141R, 141G and 141B to be adjusted are attached to the liquid crystalpanel holder 317 of the six-axis position adjusting unit 31.

[0185] Subsequently, as shown in FIG. 18, the model data is fetched inthe preliminary step S4 (S41) and the computer determines whether theoptical unit 170 of the same manufacture model is successively producedor not (model determining step: S11A). When the same model is produced,the initial setting step S42 is omitted and the CCD camera 41 is set atthe reference position based on the model data (S43). Further, thesix-axis position adjusting unit moving mechanism 31A is advanced by apredetermined distance (S44).

[0186] In other words, when the optical unit 170 of the same manufacturemodel is successively produced, the reference position of the six-axisposition adjusting unit 31 is set at the position of the six-axisposition adjusting unit 31 set during the preceding position adjustingstep S6.

[0187] Thereafter, the detection step S5 is conducted in the same manneras the first embodiment and the process proceeds to the positionadjusting step S6.

[0188] As shown in FIG. 19, in the focus adjustment step S61 of theposition adjusting step S6, the computer judges whether the optical unit170 of the same manufacture model is successively produced or not (modeldetermination step S111B). When the same manufacture model is produced,the coarse adjustment step S610 is omitted and the process proceeds tothe minute adjustment step S615.

[0189] In other words, when the optical unit 170 of the same model issuccessively produced, the initial position of the planar positionadjuster 311 of the six-axis position adjusting unit moving mechanism31A is set at the position of the planar position adjustment axis setduring the minute adjustment step S615 of the preceding focus adjustmentstep S615 (i.e. set at the focus position of preceding productionprocess).

[0190] Thereafter, by conducting the alignment adjustment step S62 as inthe first embodiment and conducting the steps of S7 to S10 aftercompleting the position adjusting step S6, a plurality of optical units170 can be successively produced.

[0191] In the above, when a malfunction is determined during pictureelement shift measurement in the S9 step, the computer 70 cancels theseries of above steps, and again conducts the same step as the firstembodiment.

[0192] According to the above second embodiment, following effects canbe obtained as well as the above effects (1) to (10).

[0193] (11) When a plurality of optical units 170 are produced and theposition of a plurality of liquid crystal panels 141R, 141G and 141B issuccessively adjusted relative to the cross dichroic prism 150, whetherthe same model is successively produced or not is determined in themodel determination steps S11A and S11B, and the initial setting stepS42 and the coarse adjustment step S610 are omitted when the same modelis determined, so that excessive process in successively producing thesame model can be eliminated.

[0194] Accordingly, the cycle time for producing the optical unit 170can be reduced and the position of a plurality of liquid crystal panels141R, 141G and 141B of a plurality of optical units 170 can besuccessively and smoothly conducted.

[0195] (12) The computer 70 conducts the same normal process as in thefirst embodiment without omitting the initial setting step S42 and thecoarse adjustment step S610 when a malfunction is determined in thepicture element shift measurement step S9. Accordingly, production ofthe optical unit 170 using the position established in producingpreceding inferior product can be avoided, thereby efficiently producinga plurality of optical units 170.

[0196] [6. Modifications]

[0197] The scope of the present invention is not restricted to the aboveembodiment but includes other arrangements as long as an object of thepresent invention can be achieved, which includes followingmodifications etc.

[0198] Though the light beam irradiated by the cross dichroic prism 150is directly imported by the surrounding CCD cameras 41 after beingrefracted by the beam splitter 451, a light beam sensor 80 may beconstructed using, for instance, a fiber scope 81 capable of introducingthe irradiated light beam as shown in FIG. 20.

[0199] In FIG. 20, though detail such as cross section thereof etc. isnot specifically illustrated, the fiber scope 81 of the light beamsensor 80 has a fiber body 82 including a light beam importing opticalfiber as a light guide for introducing and transmitting the light beamirradiated by the cross dichroic prism 150, a light-supplying opticalfiber disposed along the light beam importing optical fiber, and aninsulation for covering the optical fibers. An optical component 83installed with an objective lens etc. is provided on an end of the fiberbody 82 and a CCD unit 84 installed with an adjusting light source isconnected to the other end.

[0200] Incidentally, the fixing ultraviolet light source is provided onthe side of the liquid crystal panels 141R, 141G and 141B.

[0201] The light beam importing optical fiber is connected to the chargecoupled device in the CCD unit 84 via optical component such as a lensand the light-supplying optical fiber is connected to the adjustinglight source. The adjusting light source and the light-supplying opticalfiber constitutes light source supply according to the presentinvention.

[0202] In the light beam sensor 80 using the fiber scope 81, theposition-adjusting light beam (solid line arrow) from the adjustinglight source is initially irradiated on the cross dichroic prism 150through the light-supplying optical fiber and the optical component 83and is reflected by the liquid crystal panels 141R, 141G and 141B. Thereflected light beam (dotted line arrow) is received by the opticalcomponent 83 and is transmitted by the light beam importing opticalfiber to be received by the CCD unit 84.

[0203] Using the light beam sensor 80, since the light guide of thepresent invention is made of the light beam importing optical fiber, thelocation efficiency of the light guide can be improved using dead spaceby, for instance, bending the light beam importing optical fiber in adesired direction, so that the size reduction of the position adjustercan be further enhanced.

[0204] Further, since the position adjusting light beam is supplied fromthe side of the cross dichroic prism 150, the light source unit 37including the unit body 371 as shown in FIG. 7 is not necessary to beprovided on the side of the liquid crystal panel holder 317 of thesix-axis position adjusting unit 31, thereby simplifying the structurearound the liquid crystal panel holder 317.

[0205] Another modification of the light beam sensor may be arranged asshown in FIG. 21.

[0206] In FIG. 21, a light beam sensor 90 has a single beam splitter 451constituting the light guide provided on the incident-side of the crossdichroic prism 150, a pair of CCD cameras 41 (41A) provided opposite tothe cross dichroic prism 150 with the beam splitter 451 therebetween,and another pair of CCD cameras 41 (41B) opposing to one of theremaining two sides of the beam splitter 451. The master unit isdisposed opposing to the remaining one side of the beam splitter 451.

[0207] The beam splitter 451 of the light beam sensor 90 directlytransmits half of the light beam (solid line arrow) irradiated by thecross dichroic prism 150 to be incident on the CCD camera 41A andrefracts another half thereof by ninety degrees to introduce to the CCDcamera 41B. The beam splitter 451 also directly transmits half of thelight beam (dotted line arrow) irradiated from the reference crossdichroic prism to be incident on the CCD camera 41B and refracts anotherhalf by ninety degrees to introduce to the CCD camera 41A.

[0208] The combination of CCD cameras 41A and the CCD cameras 41B arelocated at a position corresponding to the four corners of therespective image formation area of the liquid crystal panels 141R, 141Gand 141B and the respective reference liquid crystal panels (R, G, B)and correspondingly on one diagonal line of the image formation area.

[0209] According to the above light beam sensor 90, by switching theposition-adjusting light beam supplied to the master unit and theposition-adjusting light beam to be supplied to the liquid crystalpanels 141R, 141G and 141B, the cross dichroic prism 150 and the liquidcrystal panels 141R, 141G and 141B can be adjusted and fixed whilekeeping the master unit being put on the support jig, so that usabilitythereof can be enhanced as compared to the above-described embodimentwhere the master unit has to be detached.

[0210] Though the position-adjusting light beam received by the lightbeam sensor 40 is supplied from the side of the liquid crystal panels141R, 141G and 141B in the above-described embodiment, the light may besupplied from the side of the light guide 45. Specifically, the lightbeam is initially transmitted and supplied through the beam splitter 451of the light guide 45 and the transmitted light beam is incident on thecross dichroic prism 150. Thereafter, the transmitted light beam isreflected by the liquid crystal panels 141R, 141G and 141B and thereflected light beam is entered again to the cross dichroic prism 150 tobe refracted by the beam splitter 451 to be received by the CCD camera41.

[0211] According to the above arrangement, the light source unit 37 isnot necessary to be provided on the side of the liquid crystal panelholder 317, thereby simplifying the surrounding structure.

[0212] Though the adjusting process and fixing process are sequentiallyconducted for each liquid crystal panels 141R, 141G and 141B in theabove-described embodiment, the light beam may be simultaneouslysupplied to the respective liquid crystal panels 141R, 141G and 141B andthe light beam (white light) irradiated by the cross dichroic prism 150may be received by the CCD camera (3 CCD camera) 41, so that theadjusting process and the fixing process of the liquid crystal panels141R, 141G and 141B may be simultaneously conducted.

[0213] According to the above arrangement, though the structure can becomplicated since the received light beam has to be separated into threecolors of red, green and blue by the light beam sensor 40, the timerequired for adjusting and fixing processes can be greatly reduced.

[0214] Though the liquid crystal panels 141R, 141G and 141B are used asthe optical component for modulating the light in accordance with theimage signal in the above-described embodiment, such arrangement is notrestricting. Specifically, the present invention may be applied foradjusting the position of objects other than the liquid crystal panelsuch as a device using a micro-mirror as an optical component foroptical modulation.

[0215] Other specific arrangement and configuration in implementing thepresent invention may be used as long as an object of the presentinvention can be achieved.

INDUSTRIAL AVAILABILITY

[0216] The present invention can be applied as a position adjuster of anoptical modulator for adjusting mutual position of respective opticalmodulators and a position adjusting method of an optical modulator forproducing a projector having a color separating optical system forseparating a light beam irradiated by a light source into a plurality ofcolor lights, a plurality of optical modulators for modulating therespective color lights separated by the color separating optical systemin accordance with image information, and a color combining opticalsystem for combining the light beam modulated by the respective opticalmodulators.

What is claimed is:
 1. A position adjuster of an optical modulator thatadjusts relative position of a plurality of optical modulators, theposition adjuster being used for producing a projector having a colorseparating optical system that separates a light beam irradiated by alight source into a plurality of color lights, a plurality of opticalmodulators that modulates the respective color lights separated by thecolor separating optical system in accordance with image information,and a color combining optical system that combines the light beammodulated by the respective optical modulators, the position adjustercomprising: a light beam sensor that directly receives aposition-adjusting light beam irradiated by the optical modulatorthrough the color combining optical system.
 2. The position adjuster ofan optical modulator according to claim 1, the light beam sensorcomprising: a light guide that introduces the light beam irradiated fromthe color combining optical system in a predetermined direction; and animage sensor that receives the light beam guided by the light guide andconverts the light beam into an electric signal.
 3. The positionadjuster of an optical modulator according to claim 2, wherein the lightguide includes a reflection mirror that reflects and refracts the lightbeam irradiated by the color combining optical system.
 4. The positionadjuster of an optical modulator according to claim 2, wherein the lightguide includes an optical fiber that introduces the light beamirradiated by the color combining optical system to the image sensor. 5.The position adjuster of an optical modulator according to any one ofclaims 2 to 4, wherein the light beam sensor includes a light supplythat supplies the position-adjusting light beam.
 6. The positionadjuster of an optical modulator according to any one of claims 2 to 5,wherein the light beam sensor includes a plurality of image sensors. 7.The position adjuster of an optical modulator according to claim 6,wherein the plurality of image sensors are correspondingly located on adiagonal line of a rectangular image formation area of the opticalmodulator.
 8. The position adjuster of an optical modulator according toany one of claims 1 to 7, further comprising a position adjustingportion that holds the optical modulator and adjusts the position of theoptical modulator relative to the color combining optical system, theposition adjusting portion being supported by a coarse focus adjustingmechanism that is moved toward and away from the color combining opticalsystem.
 9. A position adjusting method of an optical modulator thatadjusts relative position of a plurality of optical modulators, theposition adjusting method being used for producing a projector includinga color separating optical system that separates a light beam irradiatedby a light source into a plurality of color lights, a plurality ofoptical modulators that modulates the respective color lights separatedby the color separating optical system in accordance with imageinformation, and a color combining optical system that combines thelight beam modulated by the optical modulators, the position adjustingmethod comprising: a preliminary step that, based on a plurality ofreference optical modulators and a reference color combining opticalsystem of which relative position is adjusted in advance, sets aposition of light beam sensor capable of receiving a light beamirradiated by the reference color combining optical system; a provisionstep that sets the color combining optical system relative to the lightbeam sensor; a detection step that introduces the light beam to theoptical modulator to be adjusted for directly detecting the light beamirradiated via the color combining optical system by the light beamsensor; and a position adjusting step that adjusts the position of theoptical modulator based on the detected light beam.
 10. The positionadjusting method of an optical modulator according to claim 9, whereinthe detection step and the position adjusting step are continuouslyconducted for every optical modulator.
 11. The position adjusting methodof an optical modulator according to claim 9 or 10, wherein thepreliminary step has an initial setting step where the position of anposition adjusting portion that adjusts the position of the opticalmodulator at a predetermined designed position relative to the coarsefocus adjusting mechanism moving toward and away from the colorcombining optical system.
 12. The position adjusting method of anoptical modulator according to any one of claims 9 to 11, wherein theposition adjusting step includes a focus adjusting process whereadvancement and retraction positions relative to the color combiningoptical system are adjusted and an alignment adjusting process where themutual position of respective optical modulators is adjusted.
 13. Theposition adjusting method of an optical modulator according to claim 12,wherein the focus adjusting process includes a coarse adjusting stepwhere the focus of the optical modulator is adjusted by advancing andretracting a coarse focus adjusting mechanism that moves the opticalmodulator toward and away from the color combining optical system, and aminute adjusting step by the position adjusting portion that adjusts theposition of the optical modulator.
 14. The position adjusting method ofan optical modulator according to any one of claims 11 to 13, whereinthe position of the optical modulator is successively adjusted for aplurality of projectors, the method comprising a type determining stepin which whether the same type of projectors are successively producedor not is determined, where the initial setting step and/or the coarseadjusting step is omitted when the type of the projectors are determinedto be the same in the type determining step.